Bone Blood Flow and Vascular Reactivity

Abstract

Blood flow is essential for normal bone growth and bone repair. Like other organs, the regulation of blood flow to bone is complex and involves numerous physiologic mechanisms including the sympathetic nervous system, circulating hormones, and local metabolic factors. Our studies addressed the following questions: (1) Which endogenous vasoconstrictor agents regulate in vivo blood flow to bone? (2) Does a decrease in bone vascular reactivity to vasoconstrictor hormones account for the increase in blood flow during bone healing? (3) Does the endothelium influence bone arteriolar function? An intact bone model was developed in the rat to assess hormonal regulation of in vivo bone blood flow and in vivo bone vascular reactivity. An isolated, perfused bone arteriole preparation was employed to characterize the responsiveness of small resistance-size arterioles (diameter < 100 µm) to vasoconstrictor hormones and to evaluate the role of the vascular endothelium to modulate vascular smooth muscle reactivity. Our results indicate that: (1) though exogenous endothelin is a potent constrictor of the in vivo bone vasculature, endogenous endothelin does not actively regulate in vivo blood flow; (2) the increase in blood flow to a bone injury site is not due to a decrease in bone vascular sensitivity to norepinephrine, and (3) isolated bone arterioles of young rats are very sensitive to vasoconstrictor hormones but exhibit only modest endothelium-mediated vasodilation.

Smoking and dental implants: A systematic review and meta-analysis

“…123 Besides carrying oxygen and nutrients to bone tissue, blood flow plays an active role in bone formation and remodelling by mediating the interactions among osteoblasts, osteocytes, osteoclasts, and vascular cells at a variety of levels. 124 Furthermore, sensitivity analysis suggests that smoking significantly affects the survival of implants inserted only in the maxilla. The lack of statistical significance for the mandible is surprising but is most likely explained by the limited number of studies 16,24,28,34,35 reporting implant survival for smokers and non-smokers exclusively in the inferior jaw.…”

Uncoupled angiogenesis and osteogenesis in nicotine-compromised bone healing

“…Besides carrying oxygen and nutrients to bone tissue, blood flow play an active role in bone formation and remodeling by mediating the interactions among osteoblasts, osteocytes, osteoclasts, and vascular cells at a variety of levels. (46) The uncoupled vessel density and blood perfusion implied a complex mechanism of nicotine in controlling angiogenic activity and blood perfusion. The reduced blood flow indicates that nicotine may produce vasoconstriction during bone regeneration.…”

Computed Tomography and Optical Imaging of Osteogenesis-angiogenesis Coupling to Assess Integration of Cranial Bone Autografts and Allografts

“…μCT data can be readily analyzed using advanced tools such as IPL software. For example, the thickness analysis shown in Figure 3C revealed that the main differences between cranial autograft and allograft are in vessels ranging from 0.1 to 0.08 mm in diameter, which characterizes blood arterioles 10 . This result is consistent with studies performed in long bone model 11 .…”